Synchronous rectifier control device and forward synchronous rectifier circuit
First Claim
1. A synchronous rectifier control device coupled with the secondary side of a forward synchronous rectifier circuit, which includes:
- a condition detecting unit, which receives a detecting signal, representing the condition on the secondary side of the forward synchronous rectifier circuit, and at least one reference signal, and generates a first synchronous control signal accordingly;
a reference time circuit, which is coupled with the condition detecting unit, and generates a reference time signal based on the first synchronous control signal; and
a synchronous signal generator, which generates a second synchronous control signal according to the first synchronous control signal and the reference time signal;
wherein, when the time period of the first synchronous control signal is shorter than the time period of the reference time signal, the synchronous signal generator stops generating the second synchronous control signal.
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Abstract
Disclosed are a synchronous rectifier control device and a forward synchronous rectifier circuit. The synchronous rectifier control device is coupled with the secondary side of the forward synchronous rectifier circuit, comprising a condition detecting unit, a reference time circuit and a synchronous signal generator. The condition detecting unit receives at least one reference signal and a detecting signal in response to the condition of the secondary side of the forward synchronous rectifier circuit, and accordingly generates a first synchronous control signal. The reference time circuit is coupled with the condition detecting unit, and generates a reference time signal in response to the first synchronous control signal. The synchronous signal generator generates a second synchronous control signal in response to the first synchronous control signal and the reference time signal.
44 Citations
14 Claims
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1. A synchronous rectifier control device coupled with the secondary side of a forward synchronous rectifier circuit, which includes:
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a condition detecting unit, which receives a detecting signal, representing the condition on the secondary side of the forward synchronous rectifier circuit, and at least one reference signal, and generates a first synchronous control signal accordingly; a reference time circuit, which is coupled with the condition detecting unit, and generates a reference time signal based on the first synchronous control signal; and a synchronous signal generator, which generates a second synchronous control signal according to the first synchronous control signal and the reference time signal; wherein, when the time period of the first synchronous control signal is shorter than the time period of the reference time signal, the synchronous signal generator stops generating the second synchronous control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A forward synchronous rectifier circuit, which includes:
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a converting unit, having a primary side and a second side, wherein the primary side is coupled with an input voltage, so as to convert the power from the input voltage source to an output voltage on the secondary side; a first switch, coupled with the primary side of the converting unit; a pulse width modulation controller, controlling the switching of the first switch based on a detecting signal of the output voltage; a synchronous rectifier switch unit, having a second switch and a third switch, in which the synchronous rectifier switch unit is coupled with the secondary side of the converting unit so as to rectify the output voltage; and a synchronous rectifier control device, coupled with the secondary side of the converting unit, and generating a first synchronous control signal and a second synchronous control signal based on the condition on the secondary side so as to respectively control the second switch and the third switch, wherein the synchronous rectifier controller stops generating the second synchronous control signal when the time period of the first synchronous control signal is shorter than a predetermined time period. - View Dependent Claims (12, 13, 14)
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Specification